My eyes were tired, and I have connected a Nextion NX4827T043 display like this:
Nextion - Arduino Mega
TX - GND
RX - TX
GND - RX
5V - 5V
Now I connect it properly, but the Nextion seems to be dead. No LCD light. Even if I connect it to a 5V external power supply (mobile charger).
Is it possible that the Nextion is fried for having connected it like that?
ps: the Nextion was working before I played Mr. Magoo
Hello Pinfloid,
I'm sorry but I think you already know the answer to your question 
In any case, nothing I or anyone else can say will change the fact that it doesn't work. You could try reloading the configuration from a SD card and applying 5V, but it seems to me it's dead. This happens when you mess with electronics, occasionally you make a silly mistake and things stop working, sometime dramatically with lots of smoke, sometime quietly. We've all done similar things. Embrace it as part of the fun of electronics learn from your mistake and move on.
I've asked Nextion support the reference of the SMD component D2 in front of the TX. They have promptly replied saying that they do not provide such data and that the MCU could also probably be damaged.
Anyway, I've looked with a Mr.Magoo magnified glass and it is marked as WG5, which is a PESD5V0S2BT low capacitance bidirectional double ESD protection diode. I've already ordered it. For $0.3 I don't have much to loose! But I will give the SMD soldering job to a friend with younger eyes than me 
OK, I'd be interested to know how you get on. As you say, nothing to lose! Good luck 